This invention relates to a method and device for tying a bundle of electrical wires.
In many areas of technology and industry it is customary to tie a plurality of electrical wires together, particularly where several wires are laid in parallel over extended distances such as in electrical equipment and aircraft. In electrical motors bundles of wires forming the windings of the rotor and stator are customarily bound up together. One known method of holding bundles of wires together involves the use of separate plastic ties or binders each of which operates independently of the others. The cable binders are prefabricated as individual plastic parts and are comparatively expensive.
German Offenlegungsschrift No. 2,533,640 discloses a method and device for continuously wrapping a bundle of wires by means of a lacing or crocheting process with tying yarn laid in loops. At the end of the tying process, in which the bundle of wires has been tied continuously along its length, the end of the thread is cut off manually and tied manually. The device described in Offenlegungsschrift No. 2,533,640 comprises a housing or frame in the form of a gun at one end of which is mounted a thread spool or reel. At an end of the gun opposite the thread reel, a substantially C-shaped protector or guard and a similarly shaped guide member are pivotably mounted for rotation about an axis extending substantially perpendicularly to the plane of the gun. The guard and the guide each have U-shaped opening in which the bundle of wires is inserted, the bundle extending parallel to the axis of rotation of the guard and the guide member upon insertion of the bundle into the U-shaped opening. A pneumatic cylinder is swingably mounted to the frame at a pivot pin at an end of the frame proximate to the thread reel and spaced from the guard and the guide member. The pneumatic cylinder has a plunger or reciprocatable shaft to the free end of which is attached a latch needle for forming a series of interlocking thread loops about the bundle of wires. The plunger of the pneumatic cylinder is provided with a pin or lug extending transversely from the plunger through a wishbone-shaped slot formed in one of the plates of the frame. Upon reciprocation of the latch needle and the plunger of the pneumatic cylinder, the pin or lug moves first along one arm of the wishbone-shaped slot and then along the other arm thereof, whereby the latch needle is shifted from one side of the U-shaped opening to the other side thereof in alternating phases of a tying cycle. The pin also traverses a radially extending slot in a gear which has teeth meshing with teeth formed on an outer edge of the C-shaped guard. Upon reciprocation of the latch needle and the plunger of the pneumatic cylinder and upon the sliding motion of the pin along the arms of the wishbone-shaped slot, the gear rotates and thereby pivots the guard and the guide member about the axis along which a bundle of wires is disposed. The tying device disclosed by Offenlegungsschrift No. 2,533,640 includes an assembly for automatically varying the pressurization of the pneumatic cylinder to reciprocate the plunger and the latch needle. A trigger is provided on the device for controlling the initiation of the automatic tying operation.
In the device of German Offenlegungsscrift No. 2,533,640 it is not possible to achieve a fully automatic operation in that both the initial attachment of the yarn to the bundle of wires and the severing and knotting of the yarn at the end of the tying operation must be accomplished manually. This peculiarity of the device is considered a disadvantage by the technical community since it results in practice in a time consuming and inefficient operation.
An object of the present invention is to provide an improved device for tying a bundle of wires, which is completely suitable for one-handed operation and which decreases, if not eliminates, the extent to which manual operations are necessary.
Another object of the present invention is to provide an improved method for tying a bundle of wires, which method is fully automatic.